US2019368016A1PendingUtilityA1
Steel suitable for plastic moulding tools
Est. expiryJun 16, 2036(~9.9 yrs left)· nominal 20-yr term from priority
Inventors:Venkata Seshendra KaramcheduAnna MedvedevaChristos OikonomouJesper Erik Joachim Sparrevohn VangPetter Damm
C22C 38/44C22C 38/02B22F 10/64B22F 10/25B22F 10/28B22F 10/366B22F 10/36B22F 3/15C22C 33/0285C22C 38/06B22F 3/20C22C 38/54C23C 4/067C22C 38/04B22F 9/082C22C 33/04C22C 38/001B33Y 80/00B22F 3/105B22F 3/115B33Y 70/00B22F 1/0014B22F 1/052Y02P10/25C22C 38/50C22C 38/48
54
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Claims
Abstract
The invention relates steel suitable for plastic moulding tools. The steel comprises the following main components (in wt. %): C 0.02-0.04 Si 0.1-0.4 Mn 0.1-0.5 Cr 11-13 Ni 7-10 Mo 1-25 Al 1.4-2.0 N 0.01-0.15 optional elements and impurities balance. The invention is also directed to pre-alloyed powders made from said alloy, the use of such powder as well as AM articles produced from said powder.
Claims
exact text as granted — not AI-modified1 . A steel for making a mould for forming plastics, the steel consists of, in weight % (wt. %):
Min
Max
C
0.02
0.04
Si
0.1
0.4
Mn
0.1
0.5
Cr
11
13
Ni
7
10
Cr + Ni
19
23
Mo
1
25
Al
1.4
2.0
N
0.01
0.75
optionally
Cu
0.05
2.5
B
0.002
2.0
S
0.01
0.25
Nb
0.01
Ti
2
Zr
2
Ta
2
Hf
2
Y
2
Ca
0.0003
0.009
Mg
0.01
O
0.003
0.80
REM
0.2
Fe and impurities balance.
2 . A steel according to claim 1 , which fulfils at least one of the following requirements:
Min
Max
C
0.025
0.035
Si
0.15
0.40
Mn
0.15
0.50
Cr
11.5
12.5
Ni
8.5
10.0
Cr + Ni
20
23
Mo
1.0
2.0
Al
1.5
1.9
N
0.01
0.15
S
0.01
0.03
and/or the steel has a mean hardness in the range of 320-510 HBW 10/3000 , wherein the steel has a thickness of at least 100 mm and the maximum deviation from the mean Brinell hardness value in the thickness direction measured in accordance with ASTM E10-01 is less than 10%, and wherein the minimum distance of the centre of the indentation from the edge of the specimen or edge of another indentation shall be at least two and a half times the diameter of the indentation and the maximum distance shall be no more than 4 times the diameter of the indentation,
and/or
the steel has a cleanliness fulfilling the following maximum requirements with respect to micro-slag according to ASTM E45-97, Method A:
A
A
B
B
C
C
D
D
T
H
T
H
T
H
T
H
1.0
0
1.5
1.0
0
0
1.5
1.0
3 . A steel according to claim 1 , which is not alloyed with S and fulfils at least one of the following requirements:
Min
Max
N
0.01
0.04
Cu
0.5
2.1
Cr + Ni
20.5
22.0
Mo
1.2
1.6
S
0.01
Ti
0.01
Zr
0.01
Ta
0.01
Hf
0.01
Y
0.01
wherein the microstructure fulfils at least one of the following requirements:
the matrix comprises ≥75 vol. % martensite,
the matrix comprises ≤7 vol. % delta ferrite,
the matrix comprises 2-20 vol. % austenite,
the matrix hardness is 40-56 HRC,
the size of all AlN particles is ≤4 μm,
the un-notched impact toughness is ≥200 J,
the compressive yield strength Rc 0.2 is at 10-30% higher than the tensile yield strength Rp 0.2 .
4 . A steel according to claim 1 , which fulfils the following requirements:
Min
Max
C
0.025
0.035
Si
0.15
0.40
Mn
0.15
0.50
Cr
11.5
12.5
Ni
8.5
10.0
Cr + Ni
20
23
Mo
1.0
2.0
Al
1.5
1.9
N
0.01
0.15
wherein the microstructure fulfils at least one of the following requirements:
the matrix comprises ≥80 vol. % martensite,
the matrix comprises 4-20 vol. % austenite.
5 . A pre-alloyed powder having a composition as defined in claim 1 .
6 . A pre-alloyed powder as defined in claim 5 , wherein the powder is produced by gas atomizing, at least 80% of the powder particles have a size in the range of 5 to 150 μm the and wherein the powder fulfills at least one of the following requirements:
Powder size distribution (in μm):
5≤
D10
≤35
20≤
D50
≤55
D90
≤80
Mean sphericity, SPHT
≥0.85
Mean aspect ratio, b/1
≥0.85
wherein SPHT=4πA/P 2 , where A is the measured area covered by a particle projection and P is the measured perimeter/circumference of a particle projection and the sphericity (SPHT) is measured by a Camsizer in accordance with ISO 9276-6, and wherein b is the shortest width of the particle projection and 1 is the longest diameter.
7 . A pre-alloyed powder as defined in claim 6 , wherein at least 90% of the powder particles have a size in the range of 10 to 100 μm the and wherein the powder fulfils at least one of the following requirements:
Powder size distribution (in μm):
10≤
D10
≤30
25≤
D50
≤45
D90
≤70
Mean sphericity, SPHT
≥0.90
Mean aspect ratio, b/1
≥0.88
8 . An article formed by an additive manufacturing method using a pre-alloyed powder as defined in claim 5 , wherein the article fulfils at least one of the following requirements:
the matrix comprises ≥80 vol. % martensite, the matrix comprises ≤5 vol. % delta ferrite, the matrix comprises 2-20 vol. % austenite, the matrix hardness is 34-56 HRC, the size of all AlN particles is ≤4 μm, the Charpy V-notch value perpendicular to the build direction is ≥5 J, the tensile strength R m perpendicular to the build direction is ≥1600 MPa, the yield strength Rc 0.2 perpendicular to the build direction is ≥1500 MPa, the compressive yield strength Rc 0.2 perpendicular to the build direction is at least 10% higher than tensile yield strength Rp 0.2 .
9 . An article according to claim 8 , wherein the article is at least a part of a mould for forming plastic and wherein the article optionally fulfils at least one of the following requirements:
the matrix comprises ≥85 vol. % martensite, the matrix comprises ≤2 vol. % delta ferrite, the matrix comprises 4-15 vol. % austenite, the matrix hardness is 40-50 HRC, the Charpy V-notch value perpendicular to the build direction is ≥10 J. and/or the article has a cleanliness fulfilling the following maximum requirements with respect to micro-slag according to ASTM E45-97, Method A:
A
A
B
B
C
C
D
D
T
H
T
H
T
H
T
H
1.0
0
1.5
1.0
0
0
1.5
1.0
10 . Use of a pre-alloyed powder according to claim 5 for making a solid object by the use of any of the methods of hot isostatic pressing, powder extrusion and additive manufacturing or for providing a surface layer on a substrate by thermal spraying, laser cladding, cold spraying or overlay welding.
11 . The steel according to claim 2 , wherein the maximum deviation from the mean Brinell hardness value in the thickness direction measured in accordance with ASTM E10-01 is less than 5%.Cited by (0)
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